amtrpt

Bloomin,
For me the best thing I can do is try to really stay involved in the music. If I'm really listening then I can come right in with the orchestra.

As far as technincal advice goes, I would say try an keep your breathing nice and relaxed during the rests. Also I try to make sure I keep my mouth piece warm before the entrance. Mostly you just have to be confident and let it go. Don't try an sneak in.
Hope that's helpful.
Best,
Andrew